1. Field of the Invention
The present invention relates to a cassette loading apparatus for automatically loading a cassette into a tape driving mechanism and, more particularly, to a cassette loading apparatus which uses the driving force of a motor provided in the tape driving mechanism.
2. Description of the Related Art
Videocassette recorders generally comprise a cassette loading mechanism for loading a cassette and a tape driving mechanism for performing such functions as drawing the tape from a loaded cassette and travelling a tape for recording and reproducing information with respect thereto. In this case, although there are various types of cassette loading mechanisms, most videocassette recorders for home use adopt a front-loading type system. Such a cassette loading mechanism adopting the front loading system generally includes a cassette holder for holding an inserted cassette, a guide for movably supporting the cassette holder so that the cassette holder can move horizontally and vertically in stages, and driving means (a motor) for moving the cassette holder.
U.S. Pat. No. 4,951,164 discloses a technique for using the driving force of a motor installed in the tape driving mechanism, without an additional motor for operating the cassette loading mechanism. In particular, the tape driving mechanism comprises a head drum for use in recording and reproducing, a capstan for travelling the tape, a pinch roller, a deck having a reel driving table for driving a tape reel in the loaded cassette, and a motor for providing the deck with a drive force, such that the operational state of each part can be converted according to a mode selection.
In order to operate a cassette loading mechanism by employing the driving force of the motor installed in the tape driving mechanism, the tape driving mechanism should not be operated when cassette loading is in progress. Thus, after cassette loading, the tape driving mechanism is operated while maintaining the cassette-loaded state. With such a driving portion constituted as in the aforementioned U.S. patent, a worm wheel has a toothless portion which is secured to the motor shaft and a rack is employed for delivering the driving force of the motor to the cassette loading mechanism from the worm wheel. That is, when a cassette is first inserted, the worm and the worm wheel mesh and rotate together, so that the cassette loading mechanism loads the inserted cassette onto the deck. With the cassette thus-loaded, the worm is placed on the toothless portion of the worm wheel, such that the driving force is no longer delivered to the cassette loading mechanism but delivered to the tape driving mechanism.
In the cassette loading mechanism as described above, after the completion of a cassette loading operation, the toothless portion of the worm wheel faces the worm while the tape driving mechanism is actuated. Additionally, in order to eject a cassette, some means for rotating the worm wheel is needed so that the worm wheel and the worm can be re-connected in the above-described state. The realization of such means, however, is extremely complex, making assembly difficult. Moreover, numerous intermediate gears are needed for linking a cassette holder to the rack. Accordingly, there is excessive power loss in the drive train and cassette loading is slow.